Delivery device to deliver a staple

ABSTRACT

Apparatus for generating, applying and maintaining compression to a site in a human or animal body, the apparatus comprising: a staple comprising: a bridge configured to be elastically bendable; a first leg connected to the bridge by a first hinge region configured to be elastically bendable; and a second leg connected to the bridge by a second hinge region configured to be elastically bendable; wherein the first hinge region comprises a first hole configured to mate with a first element of a delivery device and the second hinge region comprises a second hole configured to mate with a second element of a delivery device; and wherein the first and second legs are angled toward one another when they are in an unstrained state; whereby, when the staple is mounted to a delivery device so that the first hole of the first hinge region mates with a first element of a delivery device and the second hole of the second hinge region mates with a second element of a delivery device, and when the delivery device applies a force to the bridge of the staple so as to reconfigure the bridge of the staple, the first and second legs are pivoted away from one another toward a parallel disposition.

REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. application Ser. No.15/079,770 filed on Mar. 24, 2016, which is a continuation-in-part ofU.S. patent application Ser. No. 14/540,351 filed on Nov. 13, 2014,which claims priority to U.S. Provisional Application No. 62/137,496filed on Mar. 24, 2015, U.S. Provisional Application No. 62/137,570filed on Mar. 24, 2015 and U.S. Provisional Application No. 62/238,472filed on Oct. 7, 2015.

FIELD OF THE INVENTION

The present invention relates to staples for generating, applying, andmaintaining compression to a site in a human or animal body in order tofacilitate healing of diseased or damaged tissue. The invention findsparticular utility in the field of orthopedics and specifically forreducing fractures and maintaining compression between bone fragments,and/or for reducing openings and maintaining compression between bonesegments in osteotomies, and/or for inducing fusion across the bones ofa joint in an arthrodesis. While the invention has applicationthroughout the body, its utility will be illustrated herein in thecontext of the repair of fractured or displaced bone tissue, such asduring an Akin Osteotomy of the foot or an Isolated LunocapitateArthrodesis of the hand/wrist.

BACKGROUND OF THE INVENTION

In the field of orthopedic surgery it is common to rejoin broken bones.The success of the surgical procedure often depends on the ability tore-approximate the bone fragments, the amount of compression achievedbetween the bone fragments, and the ability to sustain that compressionover a period of time. If the surgeon is unable to bring the bonefragments into close contact, a gap will exist between the bonefragments and the bone tissue will need to fill that gap before completehealing can take place. Furthermore, gaps between bone fragments thatare too large allow motion to occur between the bone fragments,disrupting the healing tissue and thus slowing the healing process.Optimal healing requires that the bone fragments be in close contactwith each other, and for a compressive load to be applied and maintainedbetween the bone fragments. Compressive strain between bone fragmentshas been found to accelerate the healing process in accordance withWolf's Law.

Broken bones can be rejoined using staples. Staples are formed from aplurality of legs (typically two legs, although sometimes more)connected together by a bridge. Staples are typically manufactured fromstainless steel alloys, titanium alloys or Nitinol, a shape memoryalloy. The legs of the staples are inserted into pre-drilled holes oneither side of the fracture line, with the bridge of the staple spanningthe fracture line.

Existing staples need to be impacted so as to make the bottom of thestaple bridge sit flush with the bone surface following implantation ofthe staple legs into the pre-drilled holes. This is because currentstaples and their associated delivery devices are typically designed togrip the staples under the bridge of the staple. After the staple hasbeen deployed from the delivery device, there is a gap between thebottom of the bridge and the top surface of the bone. A tamp istypically used to fully seat the staple bridge against the bone surface.Thus, an additional step (i.e., the tamping step) is required. Inaddition, the action of tamping can cause the bone fragments to move outof position, impairing healing.

Furthermore, current staple systems do not allow the surgeon to controlthe amount of compression that the staple will exert when it is releasedfrom the delivery device. While the shape memory and superelasticproperties allow Nitinol staples to pull together the opposing bonefragments, the recovery forces and recoverable strain generated by thesestaples may be too great and may result in the staples “tearing through”the bone tissue and thus not providing a means to generate and maintaincompression between the bone fragments.

Additionally, current staple systems do not allow the surgeon to controlthe rate at which the staple loads the bone when it is removed from thedelivery device. Current delivery devices load the bone nearlyinstantaneously. This may result in a large force impulse as thestaple's legs rapidly undergo shape recovery. This force impulse maydamage the bone and result in impaired healing.

Current staple systems also do not allow the surgeon to control theextent to which the staple's legs are opened. This can make itparticularly difficult to implant the staple into the pre-drilled holesif the holes were drilled slightly out of position. More particularly,if the pre-drilled holes are slightly too close together or slightly toofar apart, it may be difficult to fit the staple legs into the holes andmay result in impaired healing.

Finally, current staple systems do not allow for the staple to be easilyremoved following implantation. Since the staples are tamped flush withthe bone surface, there is no easy way for surgeons to grip and removecurrent staples. It is very time-consuming for surgeons to pry outdeployed staples and it is difficult to cut deployed staples forremoval. In addition, these actions may damage the underlying bone, thusimpairing healing and may result in the patient needing to be underanesthesia for a longer period of time.

Thus there exists a significant clinical need for a new staple and a newassociated delivery device to implant the staple flush with the bonesurface without the need for tamping to fully seat the staple.Additionally, there is a significant clinical need for a staple systemthat allows the surgeon to control the amount of compression the staplewill generate across the fracture line after the staple has beenimplanted into bone, to control the rate at which the staple loads thebone, to allow the surgeon to adjust opening the staple legs for properalignment with pre-drilled holes, and to allow the staple to be easilyremoved from the bone if desired.

SUMMARY OF THE INVENTION

The present invention provides a novel fixation device which is able tobring bone fragments into close proximity with each other, generate acompressive load across a fracture line and maintain that compressiveload across the fracture line while healing occurs.

Among other things, the present invention comprises the provision anduse of a novel staple which is manufactured from a shape memory material(e.g., a material capable of exhibiting superelasticity and/or atemperature-induced shape change). The shape memory material maycomprise a metal alloy (e.g., Nitinol) or a polymer (e.g., appropriatelyprocessed polyether ether ketone (PEEK)). Alternatively, the novelstaple may be manufactured from another suitable material, e.g.,stainless steel, titanium, etc. The staple is designed to reducefractures and generate and maintain compression across a fracture linebetween the bone fragments to aid in fracture healing. Note that in thepreferred form of the invention, the staple is designed to generate andmaintain compression between both the cortical bone and the cancellousbone of the bone fragments so as to promote effective healing.

In one form of the invention, the staple comprises an elastic bridge andtwo elastic legs. The bridge and the legs meet at a pair of curved hingeregions which are also elastic. The hinge regions comprise holes thatrun through the full thickness of the hinge regions and are used to matethe staple to a delivery device. In the unrestrained state, the legs ofthe staple are oriented inwardly with an angle of less than 90°(relative to the bridge) and the bridge of the staple is bowed upward.Prior to implantation, the bridge of the staple can be reversibly bentand the legs of the staple can be reversibly pivoted (e.g., by bendingat the elastic hinge regions) so that the bridge is more linear and thelegs are substantially perpendicular to the longitudinal axis of thebridge. This allows for insertion of the staple into a prepared fracturesite. A delivery device that mates with the holes in the staple's hingeregion may be used to strain the staple, or the delivery device may actas a constraint, with the staple being strained while not loaded on thedelivery device and then loaded onto the delivery device in the strainedstate. The constrained staple can then be inserted into the preparedfracture site (e.g., by positioning the staple's legs into pre-drilledholes on either side of the fracture line) and the staple can bereleased from the delivery device. Since the delivery device engages thestaple at the holes in the hinge region, the staple can be fully seatedduring implantation (i.e., the bottom of the bridge can sit on thesurface of the bone) and does not need to be tamped in order to fullyseat the staple. Releasing the staple from the delivery device allowsthe bridge and legs of the staple to attempt to return to their originalunrestrained state, thereby generating and maintaining a compressiveload while healing occurs.

In one preferred form of the invention, there is provided apparatus forgenerating, applying and maintaining compression to a site in a human oranimal body, the apparatus comprising:

a staple comprising:

-   -   a bridge configured to be elastically bendable;    -   a first leg connected to the bridge by a first hinge region        configured to be elastically bendable; and    -   a second leg connected to the bridge by a second hinge region        configured to be elastically bendable;    -   wherein the first hinge region comprises a first hole configured        to mate with a first element of a delivery device and the second        hinge region comprises a second hole configured to mate with a        second element of a delivery device; and    -   wherein the first and second legs are angled toward one another        when they are in an unstrained state;

whereby, when the staple is mounted to a delivery device so that thefirst hole of the first hinge region mates with a first element of adelivery device and the second hole of the second hinge region mateswith a second element of a delivery device, and when the delivery deviceapplies a force to the bridge of the staple so as to reconfigure thebridge of the staple, the first and second legs are pivoted away fromone another toward a parallel disposition.

In another preferred form of the invention, there is provided a methodfor generating, applying and maintaining compression to a site in ahuman or animal body, the method comprising:

providing a staple comprising:

-   -   a bridge configured to be elastically bendable;    -   a first leg connected to the bridge by a first hinge region        configured to be elastically bendable; and    -   a second leg connected to the bridge by a second hinge region        configured to be elastically bendable;    -   wherein the first hinge region comprises a first hole configured        to mate with a first element of a delivery device and the second        hinge region comprises a second hole configured to mate with a        second element of a delivery device; and        -   wherein the first and second legs are angled toward one            another when they are in an unstrained state;

providing a delivery device comprising:

-   -   a first element sized to be received in the first hole of the        first hinge region of the staple;    -   a second element sized to be received in the second hole of the        second hinge region of the staple; and    -   a plunger adapted to apply a force to the bridge of the staple        so as to reconfigure the bridge of the staple;

mounting the staple to the delivery device so that the first hole of thefirst hinge region mates with the first element of the delivery deviceand the second hole of the second hinge region mates with the secondelement of the delivery device;

applying a force to the bridge of the staple with the plunger of thedelivery device so as to reconfigure the bridge of the staple such thatthe first and second legs are pivoted away from one another toward aparallel disposition;

inserting the staple into a site in a human or animal body;

withdrawing the plunger of the delivery device from the bridge of thestaple so as to cause the staple to apply compression to the site in ahuman or animal body as the staple reconfigures; and

releasing the staple from the delivery device.

In another preferred form of the invention, there is provided a staplecomprising:

a bridge configured to be elastically bendable;

a first leg connected to the bridge by a first hinge region configuredto be elastically bendable; and

a second leg connected to the bridge by a second hinge region configuredto be elastically bendable;

wherein the first hinge region comprises a first hole and the secondhinge region comprises a second hole; and

wherein the bridge has a non-linear configuration when it is in anunstrained state, and wherein the first and second legs are angledtoward one another when they are in an unstrained state.

In another preferred form of the invention, there is provided apparatusfor securing tissue to a site in a human or animal body, the apparatuscomprising:

a staple comprising:

-   -   a bridge configured to be elastically bendable;    -   a first leg connected to the bridge by a first hinge region        configured to be elastically bendable; and    -   a second leg connected to the bridge by a second hinge region        configured to be elastically bendable;    -   wherein the first hinge region comprises a first hole and the        second hinge region comprises a second hole; and    -   wherein the bridge has a non-linear configuration when it is in        an unstrained state, and wherein the first and second legs are        angled toward one another when they are in an unstrained state;        and

at least one suture extending through (i) at least one of the first holeand the second hole, and (ii) the tissue to be secured to the site in ahuman or animal body.

In another preferred form of the invention, there is provided a staplecomprising:

a bridge configured to be plastically deformable;

a first leg connected to the bridge by a first hinge region configuredto be elastically bendable; and

a second leg connected to the bridge by a second hinge region configuredto be elastically bendable;

wherein the first hinge region comprises a first hole and the secondhinge region comprises a second hole; and

wherein the bridge has a non-linear configuration when it is in anunstrained state, and wherein the first and second legs are angledtoward one another when they are in an unstrained state.

In another preferred form of the invention, there is provided a staplecomprising:

a bridge configured to be elastic;

a first leg connected to the bridge by a first hinge region configuredto be elastically bendable; and

a second leg connected to the bridge by a second hinge region configuredto be elastically bendable;

wherein the first hinge region comprises a first hole and the secondhinge region comprises a second hole; and

wherein the first and second legs are angled toward one another whenthey are in an unstrained state.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will bemore fully disclosed or rendered obvious by the following detaileddescription of the preferred embodiments of the invention, which is tobe considered together with the accompanying drawings wherein likenumbers refer to like parts, and further wherein:

FIG. 1 is a schematic view of a novel staple formed in accordance withthe present invention, wherein the staple comprises a bridge which iscapable of being elastically bent and legs which are capable of beingelastically pivoted about elastic hinge regions, and further wherein thestaple is shown in its unstrained condition;

FIG. 2 is a schematic view of the novel staple shown in FIG. 1, whereinthe bridge of the staple has been elastically bent (i.e., made to bemore linear) and the legs of the staple have been elastically pivotedoutwards (e.g., by bending at the elastic hinge regions) so as to beperpendicular to the bridge;

FIG. 3 is a schematic view showing how the elastically bent staple ofFIG. 2 will have its legs “kick inward” when the strain on the staple isremoved;

FIGS. 4, 4A, 4B, 5, 6, 6A and 6B are schematic views showing a noveldelivery device which may be used with the novel staple shown in FIG. 1to strain and constrain the staple (e.g., with the staple legsperpendicular to the staple bridge);

FIGS. 7 and 8 are schematic views showing the delivery device of FIGS.4, 4A, 4B, 5, 6, 6A and 6B being used with the novel staple shown inFIG. 1 to elastically bend the bridge of the staple and elasticallypivot the legs of the staple (e.g., by bending at the elastic hingeregions);

FIGS. 9 and 10 are schematic views showing how the novel staple of FIG.1 may be used to generate and maintain compression between bonefragments so as to aid in fracture healing;

FIGS. 11-13 are schematic views showing another novel staple formed inaccordance with the present invention, wherein the novel staplecomprises a bridge which is capable of being elastically bent and legswhich are capable of being elastically pivoted about elastic hingeregions—the novel staple of FIGS. 11-13 has a concave bridgespecifically engineered to match the anatomy of the fracture site (e.g.,an Akin Osteotomy site), where FIG. 11 shows the staple in itsunstrained condition, FIG. 12 shows the staple strained with its bridgeelastically bent (i.e., made to be more concave) and its legs pivotedoutwards (e.g., by bending at the elastic hinge regions) so as to beperpendicular to the bridge, and FIG. 13 is a schematic view showing howthe elastically bent staple of FIG. 12 will have its legs “kick inward”when the strain on the staple is removed;

FIGS. 14-16 are schematic views showing still another novel stapleformed in accordance with the present invention, wherein the novelstaple comprises a sloped bridge which is capable of being elasticallybent and legs which are capable of being elastically pivoted aboutelastic hinge regions—the novel staple of this design has a slantedbridge specifically engineered to match the anatomy of the fracture site(e.g., an Akin Osteotomy site), where FIG. 14 shows the staple in itsunstrained condition, FIG. 15 shows the staple strained with its bridgeelastically bent (i.e., made to be more sloped) and its legs pivotedoutwards (e.g., by bending at the elastic hinge regions) so as to beparallel with each other, and FIG. 16 is a schematic view showing howthe elastically bent staple of FIG. 15 will have its legs “kick inward”when the strain on the staple is removed;

FIGS. 17-19 are schematic views showing yet another novel staple formedin accordance with the present invention, wherein the novel staplecomprises a bridge which is capable of being elastically bent and legswhich are capable of being elastically pivoted about elastic hingeregions—the staple of this design has a stepped bridge specificallyengineered to match the anatomy of the fracture site (e.g., slidingcalcaneal osteotomies, calcaneocuboid fusions, Lapidus procedures,etc.), where FIG. 17 shows the staple in its unstrained condition, FIG.18 shows the staple strained with its bridge elastically bent (i.e.,made to be more linear) and its legs pivoted outwards (e.g., by bendingat elastic hinge regions) so as to be perpendicular to the bridge, andFIG. 19 is a schematic view showing how the elastically bent staple ofFIG. 18 will have its legs “kick inward” when the strain on the stapleis removed;

FIGS. 20-22 are schematic views showing another novel staple formed inaccordance with the present invention, wherein the staple comprises amalleable bridge which is capable of being plastically bent (i.e., totake a set) and legs which are capable of being elastically pivotedabout elastic hinge regions—FIG. 20 shows the staple in its unstrainedcondition, FIG. 21 shows the staple strained with its malleable bridgeplastically bent (i.e., made to take a set so as to be concave to matchthe fracture site anatomy) and its legs pivoted outwards (e.g., bybending at elastic hinge regions) so as to be perpendicular to thebridge, and FIG. 22 is a schematic view showing how the elastically bentstaple of FIG. 21 will have its legs “kick inward” when the strain onthe staple is removed; and

FIG. 23 shows how the holes at the hinge region of the staple may beused by the surgeon to attach sutures for tying down tissue (e.g.,ligaments, tendons, etc.).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Novel StapleComprising Bridge with Two Elastic Hinge Regions Incorporating MountingHoles

Looking first at FIG. 1, there is shown a novel staple 5 which is ableto bring bone fragments into close proximity with each other, generate acompressive load across the fracture line, and maintain a compressiveload across the fracture line while healing occurs. Staple 5 can befully seated against the bone fragments without needing to be tampedafter being released from the delivery device.

Novel staple 5 is preferably manufactured from a shape memory material(e.g., a material capable of exhibiting superelasticity and/or atemperature-induced shape change). The shape memory material maycomprise a metal alloy (e.g., Nitinol) or a polymer (e.g., appropriatelyprocessed PEEK). Alternatively, staple 5 may be manufactured fromanother suitable material, e.g., stainless steel, titanium, etc. Staple5 is designed to reduce fractures and generate and maintain compressionbetween bone fragments (e.g., across a fracture line) so as to aid infracture healing. Staple 5 comprises an elastic bridge 10 and twoelastic legs 15. Bridge 10 and legs 15 meet at a pair of curved hingeregions 20 which are also elastic. Hinge regions 20 have holes 25passing therethrough. Holes 25 may be round or may have otherconfigurations consistent with the present invention. Legs 15 may havebarbed teeth 30 to help the legs of the staple grip the bone afterimplantation into the bone and prevent the legs of the staple fromworking their way back out of the bone. In its unrestrained state,bridge 10 is bowed upwardly in the manner shown in FIG. 1. In theunrestrained state, legs 15 of staple 5 are elastically pivoted inwardlyat elastic hinge regions 20 with an angle of less than 90° (relative tobridge 10). By way of example but not limitation, in one preferred formof the invention, legs 15 extend at an angle of about 65° to thelongitudinal axis of bridge 10 when in their unrestrained state.

Prior to implantation, bridge 10 of staple 5 can be reversibly bent(i.e., bent to nearly linear) and legs 15 of staple 5 can be reversiblypivoted at elastic hinge regions 20 (e.g., by bending at the elastichinge regions 20) to a position substantially perpendicular to bridge 10(FIG. 2) so as to allow for insertion of the legs of the staple into aprepared fracture site, with the bridge of the staple spanning acrossthe fracture line (see below). Note that where staple 5 is formed out ofNitinol, elastic deformations of up to approximately 8% are achievable.A delivery device (see below) can be used to elastically bend bridge 10and pivot legs 15 at elastic hinge regions 20 (e.g., by bending at theelastic regions 20), constrain and hold the staple in its strained stateprior to implantation, and then insert the staple into the preparedfracture site.

Upon insertion of the strained staple 5 into the prepared fracture site,the constraint on bridge 10 and legs 15 is removed, whereupon staple 5attempts to return to its original un-restrained state (FIG. 3), therebygenerating a compressive load across the fracture line and maintainingthat compressive load across the fracture line while healing occurs.

Looking next at FIGS. 4, 4A, 4B, 5, 6, 6A, 6B, 7 and 8, there is shown anovel delivery device 35 which may be used to selectively bend bridge 10and to selectively pivot legs 15 of staple 5 at elastic hinge regions 20(e.g., by bending at the elastic hinge regions 20). Delivery device 35comprises a body 40 having an internal threaded region 45 (FIG. 6)configured to mate with threaded screw 50. Threaded screw 50 has ahandle 55 mounted to its proximal end. Advancing threaded screw 50 intobody 40 (e.g., by selectively rotating handle 55 so as to selectivelyrotate threaded screw 50 such that the threads of threaded screw 50engage internal threaded region 45) causes the distal end of threadedscrew 50 to push against the proximal end of a plunger 60. The distalend of plunger 60 engages elastic bridge 10 of staple 5. When plunger 60is moved distally (i.e., by moving threaded screw 50 distally byrotating handle 55), the distal end of plunger 60 engages elastic bridge10 of staple 5 and elastically bends elastic bridge 10 into a morelinear configuration. Staple 5 is releasably mounted to delivery device35 by a pair of pins 65 which are mounted to two arms 70 which are eachpivotally mounted to body 40 of delivery device 35 by a pivot pin 75.Pins 65 are received within holes 25 formed in staple 5. When plunger 60is moved distally against elastic bridge 10 of staple 5, the deforming(i.e., straightening) bridge 10 of staple 5 causes arms 70 of deliverydevice 35 to pivot outwardly, with elastic hinge regions 20 of staple 5bending about pins 65 so as to pivot staple legs 15 outwardly.

More particularly, and looking now at FIGS. 7 and 8, when staple 5 ismounted to pins 65 of delivery device 35 (i.e., with pins 65 beingreceived within holes 25 of staple 5) and handle 55 is rotated so as toadvance threaded screw 50 distally, plunger 60 is also advanceddistally, whereby to push against elastic bridge 10, causing elasticbridge 10 to bend and become more linear, and causing arms 70 ofdelivery device 35 to articulate (i.e., pivot) outwardly. As thisoccurs, elastic hinge regions 20 of staple 5 bend about pins 65, causingelastic legs 15 to be pivoted about elastic hinge regions 20 so as to beoriented generally perpendicular to elastic bridge 10 (FIG. 8).

Note that staple 5 is configured so that the force that is generated asstaple 5 reconfigures (i.e., as bridge 10 and legs 15 attempt to returnback to their original disposition) is less than the “tear through”force of the bone receiving legs 15, i.e., staple 5 is specificallyengineered so as to not “tear through” the bone tissue when staple 5attempts to return to its original, unbiased shape. The compressiveforces generated by staple 5 as staple 5 attempts to reconfigure (i.e.,as bridge 10 contracts and as elastic legs 15 of staple 5 attempt topivot inboard toward one another about elastic hinge regions 20) can becontrolled by modulating the material properties of staple 5 and/or thegeometry of staple 5.

By way of example but not limitation, the percentage of cold work in theshape memory material forming staple 5 affects the compressive forcethat is generated by the reconfiguring staple 5. As the percentage ofcold work increases, the compression force that is generated decreases.In one preferred form of the present invention, staple 5 has betweenabout 15% and about 55% cold work in order to control the recovery force(i.e., the compressive force generated by bridge 10 and legs 15 asstaple 5 reconfigures) of staple 5; however, if desired, other degreesof cold work may be used, and/or the material comprising staple 5 maynot be cold worked at all.

By way of further example but not limitation, another material propertythat affects the compression force generated by staple 5 as the staplereconfigures is the temperature differential between the body thatstaple 5 will be implanted into (assumed to be approximately 37° C.,which is the temperature of a human body) and the austenite finishtemperature of the shape memory material forming staple 5. A smallertemperature differential between the two will result in staple 5generating a smaller compressive load as staple 5 reconfigures;conversely, a larger temperature differential between the two willresult in staple 5 generating a larger compressive load as staple 5reconfigures. The shape memory material that staple 5 is made out ofshould, preferably, have an austenite finish temperature of greater thanabout −10° C., resulting in a temperature differential of about 47° C.when the staple is implanted (assuming that the staple is implanted in ahuman body).

By way of further example but not limitation, staple geometry alsoaffects the compression forces generated as staple 5 reconfigures. Moreparticularly, the cross-sectional areas of elastic bridge 10, elastichinges 20 and elastic legs 15 affect the compression forces generated bythe reconfiguring staple 5. As the cross-sectional areas increase, thecompression forces that the reconfiguring staple 5 generates alsoincrease.

Elastic legs 15 of staple 5 are critical for transmitting thecompression force to the bone without “tearing through” the bone. Theheight, width, and length of the staple legs, and the geometry of thestaple legs, are all significant factors relating to the staple'sability to not “tear through” the bone. Elastic legs 15 having greatersurface area are better able to distribute the compression force andthus resist “tearing through” the bone.

FIG. 9 shows how staple 5 may be used to reduce a fracture and generateand maintain compression between bone fragments 80 and 85.

More particularly, the fracture 90 which is to be fused is firstre-approximated and reduced. A drill guide (not shown) of the sort wellknown in the art is used to drill two holes 95 the correct distanceapart to accommodate the legs 15 of staple 5. Staple 5 is mounted topins 65 of delivery device 35, and delivery device 35 is used to bendbridge 10 and straighten legs 15 of staple 5 in the manner discussedabove (i.e., by turning handle 55 to advance plunger 60 which is used tobend bridge 10 and pivot legs 15 at elastic hinge regions 20). Whilestill mounted to pins 65 of delivery device 35, legs 15 of staple 5 areplaced into the pre-drilled holes 95. Staple 5 is then released frompins 65 of delivery device 35, i.e., by turning handle 55 in theopposite (e.g., counter-clockwise) direction and sliding staple 5 off ofpins 65. This allows the bent bridge 10 and pivoted legs 15 of staple 5to attempt to return (reconfigure) to their un-bent configuration,thereby applying compression across fracture 90.

Note that in the preferred form of the invention, staple 105 is designedto generate and maintain compression between both the cortical bone andthe cancellous bone of the bone fragments so as to promote effectivehealing. In this respect note also that, while bridge 10, elastic hinges20 and the proximal (i.e., bridge-side) portions of legs 15 typicallyengage cortical bone, the pivoting nature of the reconfiguring distalportions of legs 15 will help apply enhanced compressive forces to thecancellous bone (i.e., the interior bone) of the bone fragments.

Significantly, it should be appreciated that since staple 5 is mountedto delivery device 35 via pins 65 being inserted into holes 25, staple 5can be fully inserted into pre-drilled holes 95 with bridge 10 in directcontact with bone fragments 80 and 85. Tamping is not needed in order tofully seat staple 5 (FIG. 10).

It should also be appreciated that, if desired, staple 5 can be used toattach soft tissue to bone (e.g., to attach a rotator cuff to bone).

In some circumstances it can be desirable to modify delivery device 35so as to ensure that legs 15 cannot be pivoted at hinge regions 20beyond 90 degrees (relative to the longitudinal axis of bridge 10) whenlegs 15 of staple 5 are pivoted outboard. In other circumstances, it maybe desirable for delivery device 35 to allow legs 15 of staple 5 to bepivoted outboard less than, or greater than, 90 degrees to allowinsertion into slightly mispositioned (or angled) drill holes 95.

It should be appreciated that following implantation, if desired,delivery device 35 can also be used to remove staple 5 from the bone.More particularly, delivery device 35 can be used to re-engage staple 5at the holes 25 (i.e., by inserting pins 65 of delivery device 35 intoholes 25 of staple 5) in the hinge regions 20 of staple 5. Turninghandle 55 (e.g., clockwise) causes plunger 60 to bend staple bridge 10and to reconfigure staple 5 such that bridge 10 is substantiallyperpendicular to staple legs 15. Staple 5 can then be removed from thebone by pulling the staple out perpendicular to the bone.

Additionally, staple delivery device 35 allows the surgeon to “sense”how much compression staple 5 will exert on the bone when it is releasedfrom delivery device 35 and attempts to reconfigure. More particularly,as the surgeon turns handle 55 to straighten bridge 10 and open staplelegs 15 (e.g., by turning handle 55 clockwise), handle 55 requiresgreater levels of torque as staple 5 is opened (i.e, as bridge 10 ispushed down and legs 15 are pivoted outboard), thereby providing adegree of tactile feedback to the surgeon. The torque that the surgeonapplies to handle 55 is proportional to the compression that staple 5will exert on the bone as the staple reconfigures.

Thus delivery device 35 also allows the surgeon to ascertain and controlhow much compression staple 5 will exert when the staple is releasedfrom delivery device 35. The greater the degree to which bridge 10 isstraightened and legs 15 of staple 5 are opened (i.e., pivotedoutboard), the more compressive force staple 5 will exert on the bonewhen it is released from delivery device 35.

Additionally, delivery device 35 also allows the surgeon to control therate at which staple 5 loads the bone as the staple is removed fromdelivery device 35. More particularly, turning handle 55 of deliverydevice 35 counterclockwise releases the downward (i.e., distal) forcethat plunger 60 exerts on bridge 10 of staple 5. This allows staple 5 toattempt to recover (i.e., reconfigure) to its original shape and applycompression across the fracture site. It may be desirable to allow thesurgeon to be able to control this “release rate” so that the bone isnot damaged as staple 5 reconfigures and so that staple 5 remains in thedesired location.

In one preferred form of the invention, staple 5 and delivery device 35are provided in the form of a sterilized kit. Staple 5 may be“pre-loaded” (i.e, mounted) onto delivery device 35 (i.e., with pins 65of delivery device 35 extending through holes 25 of staple 5). Staple 5may be mounted on delivery device 35 in an unconstrained or aconstrained state. The kit may include additional instruments to aid inthe implantation of the staple (e.g., k-wire, drill bit, staple sizeguide, etc.).

Example

The compressive force generated by staples of the present inventionformed out of Nitinol with greater than 20% cold work are able togenerate 50 to 100 Newtons of force depending on the staple dimensions.This is more than twice the compression force able to be generated byconventional staples of a similar size.

Alternative Configurations of Novel Staple Formed in Accordance with thePresent Invention

Looking now at FIGS. 11-19 it should be appreciated that staple bridge10 may be formed so as to have a different configuration. By way ofexample but not limitation, it may be beneficial for staple bridge 10 tohave a concave geometry (FIGS. 11-13), such that when bridge 10 ofstaple 5 is reversibly bent (i.e., so that legs 15 are pivoted so thatthey are parallel to each other), bridge 10 can bend downwardly, i.e.,so as to become more concave (FIG. 12). Upon insertion of the strainedstaple 5 across the prepared fracture site, the constraint on bridge 10and hinges 20 is removed, whereupon staple 5 attempts to return (i.e.,reconfigure) to its original unrestrained state (FIG. 13), therebygenerating a compressive load across the fracture line and maintainingthat compressive load across the fracture line while healing occurs. Byway of example but not limitation, it may be beneficial to provide astaple 5 having a concave bridge 10 for the treatment of fractures wherethe anatomy is “hour-glass” shaped (e.g., in an Akin Osteotomy).

It may also be desirable to provide a staple 5 having a bridge 10 formedwith a sloped geometry (FIG. 14). In this form of the invention, legs 15can be elastically pivoted so as to be parallel to one another (FIG.15). Upon insertion of the strained staple 5 into the prepared fracturesite, the constraint on bridge 10 and hinges 20 is removed, whereuponstaple 5 attempts to return to its original un-restrained state (FIG.16), thereby generating a compressive load and maintaining thatcompressive load while healing occurs. It may be desirable to providestaple 5 having this configuration for the treatment of fractures wherethe anatomy is non-linear (e.g., at the metaphyseal flares).

It may also be desirable to provide staple 5 with bridge 10 having astepped geometry (FIG. 17). In this form of the invention, when staple 5is reversibly strained (i.e., so that legs 15 are pivoted outboard so asto be parallel to each other), bridge segments 10 a and 10 b areparallel to each other (FIG. 18). Upon insertion of the strained staple5 into the prepared fracture site, the constraint on bridge 10 andhinges 20 is removed, whereupon staple 5 attempts to return (i.e.,reconfigure) to its original un-restrained state (FIG. 19), therebygenerating a compressive load across the fracture line and maintainingthat compressive load across the fracture line while healing occurs. Itmay be desirable to provide a staple 5 having this configuration for thetreatment of fractures where the anatomy is uneven (i.e., slidingcalcaneal osteotomies, calcaneocuboid fusions, Lapidus procedures,etc.).

Novel Staple Having a Malleable Bridge which is Plastically Deformableto Take a Set

It may also be desirable to provide a staple 5 having a malleable bridge10 which is plastically deformable so as to be able to take a set (FIG.20). This allows the surgeon to shape staple bridge 10 in order toconform to the anatomy of the patient. With this form of the invention,delivery device 35 can be used to deform/shape staple bridge 10. When astaple of this configuration has a force applied to its bridge 10 sothat staple legs 15 are pivoted so as to be parallel to each other,malleable bridge 10 is plastically deformed so as to take a set (FIG.21). The more staple legs 15 are opened (i.e., pivoted outboard), themore staple bridge 10 is plastically deformed. Upon insertion of thestrained staple 5 into the prepared fracture site, elastic hinges 20attempt to return staple legs 15 to their original un-restrained statewhile staple bridge 10 remains deformed (FIG. 22), thereby generating acompressive load and maintaining that compressive load across thefracture line while healing occurs. A staple of this configuration maybe beneficial for the treatment of fractures where the anatomy is uneven(e.g., in an Akin Osteotomy).

Additional Use for Staple Mounting Holes

While holes 25 are primarily used for releasably mounting staple 5 todelivery device 35 (i.e., via pins 65), holes 25 also may be used afterimplantation to aid the surgeon with tying ligaments and/or tendonsdirectly down to the bone (FIG. 23). Typically, a surgeon would use asuture anchor, bone tunnel or other method/device known in the art tore-secure a ligament and/or tendon to the bone. It should be appreciatedthat the staple of the present invention provides the surgeon with holes25 which may be used to tie ligaments and/or tendons directly to thebone. This allows the surgeon to avoid having to use an additionalimplant or perform an additional procedure to achieve the same outcome.

Additional Applications

In the foregoing disclosure, novel staple 5 and novel delivery device 35are discussed in the context of rejoining a broken bone. However, itshould be appreciated that novel staple 5 and novel delivery device 35may be used to promote joinder of substantially any two (or more) bonesegments, e.g., they may be used to reduce openings and maintaincompression between bone segments in osteotomies, or they may be usedfor inducing fusion across the bones of a joint in an arthrodesis, etc.

Modifications of the Preferred Embodiments

It should be understood that many additional changes in the details,materials, steps and arrangements of parts, which have been hereindescribed and illustrated in order to explain the nature of the presentinvention, may be made by those skilled in the art while still remainingwithin the principles and scope of the invention.

What is claimed is:
 1. A delivery device comprising: a) a body having aninternal threaded region configured to mate with a threaded screw; b) ahandle mounted to a proximal end of the threaded screw; and c) aplunger; wherein when the threaded screw is advanced into the body i) adistal end of the threaded screw pushes against a proximal end of theplunger, and ii) a distal end of the plunger is configured to engage andbend an elastic bridge of a releasably mounted staple.
 2. The deliverydevice of claim 1, wherein the staple comprises nitinol.
 3. The deliverydevice of claim 1, wherein the staple comprises polyether ether ketone(PEEK).
 4. The delivery device of claim 1, wherein the distal end of theplunger engages a proximal surface of the staple.
 5. The delivery deviceof claim 1, wherein side surfaces of the bridge of the staple aresubstantially flat.
 6. The delivery device of claim 1, wherein thestaple is distal of the threaded screw.
 7. The delivery device of claim1, wherein the staple and the threaded screw do not contact each other.8. A delivery device comprising: a) a body having an internal threadedregion configured to mate with a threaded screw; b) a handle mounted toa proximal end of the threaded screw; and c) a plunger; wherein when thethreaded screw is advanced into the body i) a distal end of the threadedscrew pushes against a proximal end of the plunger, and ii) a distal endof the plunger is configured to engage and bend an elastic bridge of areleasably mounted staple to become more linear.
 9. The delivery deviceof claim 8, wherein the staple comprises nitinol.
 10. The deliverydevice of claim 8, wherein the staple comprises polyether ether ketone(PEEK).
 11. The delivery device of claim 8, wherein the distal end ofthe plunger engages a proximal surface of the staple.
 12. The deliverydevice of claim 8, wherein side surfaces of the bridge of the staple aresubstantially flat.
 13. The delivery device of claim 8, wherein thestaple is distal of the threaded screw.
 14. The delivery device of claim8, wherein the staple and the threaded screw do not contact each other.